Orion Nebula

The Orion Nebula, or Messier 42, is a bright star-forming nebula in Orion, about 1,300 light-years from Earth and visible to the unaided eye.

H II region: A region of ionized hydrogen surrounding hot stars that emit ultraviolet radiation. Ultraviolet light from the Trapezium stars ionizes much of the nebula’s hydrogen.
Orion Molecular Cloud Complex: A vast complex of molecular clouds and young stars in the constellation Orion. The nebula is one active star-forming region within this larger complex.
Molecular cloud: A cold, dense interstellar cloud composed primarily of molecular hydrogen. Gravitational collapse within molecular material produced the nebula’s young stars.
Hubble Space Telescope: A space telescope operating mainly at visible, ultraviolet, and near-infrared wavelengths. Its detailed images resolved disks, jets, and gas structures within the nebula.
Horsehead Nebula: A dark nebula in Orion shaped like a horse’s head against a luminous background. Unlike bright M42, it is seen chiefly as a silhouette against emission.
Trapezium Cluster: A compact group of young, massive stars at the center of the Orion Nebula. Its brightest members illuminate and heat the nebula’s central gas.
Orion Nebula Cluster: A dense population of young stars embedded in and around the Orion Nebula. The nebula’s gas surrounds the cluster formed from the same cloud.
Star formation: The process by which dense regions of interstellar gas collapse to form stars. The nebula displays this process while massive stars are still forming nearby.
James Webb Space Telescope: A space observatory designed primarily for infrared astronomy. Infrared observations reveal embedded young stars and dusty regions obscured in visible light.
Lagoon Nebula: A large emission nebula and star-forming region in the constellation Sagittarius. It is another prominent H II region, but lies in a different constellation and environment.

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